Automatic oil pressure switch valve

ABSTRACT

An automatic oil pressure switch valve adapted to an oil supply system and being operative by pushing merely the switch for regulating an electro-magnetic switch valve whereby an oil pressure press is actuated and when a desired pressure is attained, a ram is moved backward to stop the press so that only a pushing of the switch is sufficient each time to fix the means being handled and hence there occurs no excessive strain on the switch valve to actuate so that such component will not easily break down. A pilot pressure is regulated by being introduced into a low pressure passage from an extaordinarily high pressure pump whereby a satisfactory precision of regulation is possible without employing a special electro-magnet and pressure switch.

United States Patent [151 3,661,179 Hasumi 1 May 9, 1972 s41 AUTOMATIC OIL PRESSURE SWITCH 3,439,584 4/1969 Kaptur ..9l/461 x VALVE 3,524,386 8/1970 Cudnohufsky ..9l/46l [72] lnventor: Kingo l-Iasumi, Omiya, Japan [73] Assignee: Sanwa Tetsuki Kogyo Kabushiki Kaisha,

Tokyo-To, Japan [22] Filed: June 9, 1970 [21] Appl. No.: 44,750

[30] Foreign Application Priority Data Feb. 20, 1970 Japan ..45/l4l75 [52] US. Cl ..137/596.l2 [51] Int. Cl ..Fl6k 11/10 [58] Field ofSearch ..137/596.l2, 596.l4,596.16, 137/596.l8, 625.64; 91/461, 304, 305, 306

[56] References Cited UNITED STATES PATENTS 3,395,617 8/1968 Kaptur ..91/46l X Primary Examiner-Henry T. Klinksiek Attorney-Holman & Stern [57] ABSTRACT An automatic oil pressure switch valve adapted to an oil supply system and being operative by pushing merely the switch for regulating an electro-magnetic switch valve whereby an oil pressure press is actuated and when a desired pressure is attained, a ram is moved backward to stop the press so that only a pushing of the switch is sufficient each time to fix the means being handled and hence there occurs no excessive strain on the switch valve to actuate so that such component will not easily break down. A pilot pressure is regulated by being introduced into a low pressure passage from an extaordinarily high pressure pump whereby a satisfactory precision of regulation is possible without employing a special electro-magnet and pressure switch.

1 Claim, 2 Drawing Figures PATENTEDMAY sum 3,661,179

3 FIG.!

FIG.2

8 4a4b4c4d II.

' 9 'INVENTOR 2 4 I I2 9 -3 W ATTORNEYS AUTOMATIC OIL PRESSURE SWITCH VALVE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic switch valve operated by low oil pressure adapted to an oil supply system having a single acting pressure rarn wherein the valve can be automatically switched by low oil pressure when the pressure of flowing oil against the press reaches a desired high value, so as to cause the flow of oil to the press to stop and the pressure to lower.

The object of the present invention is to provide a new and improved switch valve operated automatically by oil pressure, especially used for controlling such extraordinarily high oil pressure as 500-1 ,OOOkg/cm.

2. Description Of the Prior Art Heretofore, for controlling such extraordinarily high pressure, a special electro-magnet and a pressure regulator for high pressure have been employed.

However, the use of such special devices has made the construction large, resulting in not only a high cost of manufacture, but also unsatisfactory precision.

The provision of the present invention will eliminate such faults as described.

SUMMARY OF THE INVENTION An automatic oil pressure switch valve having a single acting press ram by which a spool valve of a main cylinder is actuated to move in alternate directions by switching an electromagnetic switch valve arranged in a low pressure relief passage communicating with a space at one end of a pilot piston of a switch cylinder via an electric switch valve, a check valve and a low pressure relief valve leading to one of a plurality of annular grooves provided for the main cylinder.

The main cylinder has a spool valve slidably positioned therein and spring biased at one end thereof, with the cylinder having a plurality of axially spaced annular grooves. One of the grooves, via a receiving passage, communicates with an oil pressure pump, another of the grooves communicates with a low pressure relief passage, another of the grooves via a delivery passage communicates with an oil pressure press and the last groove through an exhaust oil passage with an exhaust oil pipe, with the reciprocation of the spool valve forcing oil flow into the delivery passage or the low pressure relief passage, selectively. 1

The switch cylinder has slidably mounted therein a pilot piston which is spring biased at one end with the space around the spring being in communication with an exhaust oil passage leading to the exhaust oil pipe, and a second space at the opposite end piston being opened to the low pressure relief passage and a check valve adjacent the spring at the front face of the pilot piston being capable of opening and closing by the reciprocation of such pilot piston.

The objects and advantages of the invention will become more readily apparent to persons skilled in the art from the following detailed specification and annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevational cross-sectional view of the device contemplated herein; and

FIG. 2 is a view in cross section and partly in elevation of the spool valve in the main cylinder of FIG. 1 in its retracted position or with the spring compressed.

DETAILED DESCRIPTION Referring now more particularly to the drawings, there is illustrated a new and improved switch valve having housings 2 and 3 on opposite sides of a body 1 fixed integrally therewith, comprising a main cylinder 4, a switch cylinder 5, a relief passage 6 for high pressure, a switch passage 7 and a relief passage 8 for low pressure.

Mounted within the main cylinder 4 for sliding movement is a spool type valve 9 having axially spaced lands 9a, 9b, 9c of different lengths. A coil spring 10 surrounds extension 9d of the valve 9 and is biased between the base of the cylinder 4 and the end face of the land 9c to nonnally displace the valve to the position shown in FIG. 1. Axially spaced annular grooves 40, 4b, 4c and 4d communicate with the cylinder 4. The groove 4c communicates, via a delivery passage 11, with an oil pressure press R and the groove 44 with a low pressure relief passage 8. The slot 4b, via receiving passage 12, communicates with an oil pressure pump P and the slot 4d through an exhaust oil passage 17 with an exhaust oil pipe (not shown) which leads to an oil tank T.

The pump 12 delivers pressure oil selectively through passage 12 by reciprocation of the valve 9 to either be delivered to passage 9 or the low pressure relief passage 8. With the valve in the position illustrated in FIG. 1, the land 9b prevents flow from the passage 12 to the passage 8 but allows flow via groove 4b, cylinder 4, groove 40 and delivery passage 11 to the press R. When the valve 9 is in the position shown in FIG. 2, oil flow is permitted through receiving passage 12, groove 4b, cylinder 4, and groove 40 to the relief passage 8 with the land 9b blocking flow to the groove 4c and delivery passage 11.

The switch cylinder 5 has a pilot piston 13 slidably located therein, with a spring 14 biased between one end wall of the cylinder 5 and a face of the piston 13 and at the other end is supported by the face of the piston 13 of a rod 15 having a manipulating handle with the rod being threaded into the housing 3.

A check valve 16 consisting of a ball seat 16a, a ball 16b and a spring is provided at the left in the drawing (hereinafter referred to front of the pilot piston 13, which valve is opened or closed according to the reciprocation of the pilot piston 13 or of the rod 15 which is usually kept rearward to maintain the valve closed. The check valve 16 controls passage 70 located between the switch passage 7 and the cylinder 5, and it will be noted that the piston 13 is provided with an extension 13a which, when the piston 13 is displaced towards the left (FIG. 1) will remove the ball 16b from the seat 16a thereby providing communication between the switch passage 7 and the cylinder 5. An exhaust oil passage 17a opens in a space 17b of the pilot piston 13 and communicates with the oil tank (T) through the exhaust oil pipe and a space to the rear of the pilot piston 13 opens into the end of the low pressure relief passage 8.

The high pressure relief passage 6 which branches from the delivery passage 12, communicates with the space around the spring 10 through a throttle valve 18, and via another branch with the oil exhaust pipe through the high pressure relief valve (H). The switch passage 7 via branch 7b, communicates with the space at the opposite side of the land 9c through a check valve 19 similar to check valve 16 and also with the stop valve 16 through the branch 7a. The low pressure relief passage 8 which opens into the groove 40 of the cylinder 4 communicates with the space to the rear of the pilot piston 13 through a low pressure relief valve (L), a check valve 20 and an electro-magnetic switch valve 21 of a solenoid type which changes the oil flow of the low pressure relief passage 8 by closing or opening the solenoid switch. FIG. 1 shows the passage being shut and which will be opened by switching the switch valve 21. The switch passage 7 and the low pressure passage 8 are provided with accumlators 22 and 23 respectively for facilitating action of the parts which are influenced by the oil pressure moving through the open passage, of which pressure is forced by a step plate biased with the spring when the oil pressure at the passage is in a desired pressure.

As shown in FIG. 1, oil is delivered through the receiving passage 12, the grooves 4b and 4c and the delivering passage 11 into the oil pressure press (R), while the check valve 16 and the switch passage 7 are shut and while the groove 40 is being shut by the the land 9b of the valve 9, the low pressure relief passage 8 is also closed. However, when the oil pressure exceeds the predetermined value after continuing delivery of oil, the high pressure relief valve (H) is opened, and at the same time the oil pressure in the spring chamber of the spool valve 9 comes down by the action of the throttle valve 18, and the spool valve 9 slides rearward as shown in FIG. 2 smoothly facilitated by the accumulator 22, after which the oil in the oil pressure press (R) flows back into the oil tank (T) through the delivery passage 11 in a reverse manner and through the grooves 4c and 4a.

The oil in the receiving passage 12 flows away into the tank (T) through the groove 4a, the low pressure relief valve (L), the check valve and the electro-magnetic switch valve 21.

In order to actuate the oil pressure press (R) to operate again, the low pressure relief passage 8 is opened by depressing the electro-magnetic switch valve 21 to shift the valve.

Upon removing pressure from the switch of the valve 21, the spool valve 9 moves forward as shown in FIG. 1, while low pressure oil flows into the rear space of the pilot piston 13 which is forced to open the check valve 16, being facilitated by the accumlator 23 which insures opening of the valve 16, whereby the switch passage 7 communicates with the exhaust oil passage 17 loosing the pressure therein so that the balance of pressure in both spaces is lost, whereby the spool valve 9 moves forward and oil is delivered to the oil pressure press (R) through the grooves slot 4b and 4c, and such operation as described above is repeated again and again.

The rod 15 is employed to operate the check valve 16 instead of the electromagnetic switch valve 21 for the purpose of checking every part. The electro-magnetic switch valve is protected by the low pressure relief valve (L).

The construction and the operation of the present invention are such that the size and the weight of a device employing the present oil pressure switch valve can be manufactured sufficiently small and light in weight to transport, for an example, by those who work to connect wires on an electric pole where they carry only a portable single acting press and a switch for actuating the electro-magnetic switch valve set on the ground being connected with an oil pressure pump having the switch valve of this invention.

Thus the automatic oil pressure switch valve is not only useful and convenient but also readily manufactured at a low cost.

Although the present invention has been described in conjunction with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

I claim:

1. In an automatic switch valve operated by low oil pressure adapted to an oil supply system having an oil pressure press in which the switch valve can be automatically switched by low oil pressure when the pressure of the flowing oil reaches a desired high value to cause the flow of oil to the ram to stop and the pressure to lower, a main cylinder, a balancing piston positioned for reciprocation in the main cylinder, a spring within the main cylinder at one end of the piston, an oil pump, an exhaust oil conduit, an oil tank with which the exhaust oil conduit communicates, a switch cylinder, a pilot piston in the switch cylinder, said main cylinder having a plurality of axially spaced grooves, a first of said grooves communicating with the oil pump via a receiving passage, a second of said grooves being open to a low pressure relief passage, a third of said grooves communicating with the oil pressure press via a delivery passage, and a fourth of said grooves communicating with the exhaust oil conduit via an exhaust oil passage, the reciprocation of the balancing piston directing oil flow into the delivery passage or the low pressure relief passage, selectively, a spring within the switch cylinder at one end of the pilot piston, the space around the spring being open to the exhaust oil passage, the space at the other end of the ilot piston being open to the low pressure relief passage, a c eck valve communicating with the space around the spring and being capable of opening and closing by the reciprocation of the pilot valve, an electro-magnetic switch valve arranged in the low pressure relief passage open to the space around the spring for the pilot piston via an electric valve, a check valve and a low pressure relief valve leading to one of the grooves in the main cylinder, a high pressure relief passage leading to the exhaust oil conduit via a high pressure relief valve, said high pressure relief passage having a branch from the delivery passage communicating with the space around the spring for the balancing piston via a throttle valve, and a further branch leading to a switch passage communicating with the check valve. 

1. In an automatic switch valve operated by low oil pressure adapted to an oil supply system having an oil pressure press in which the switch valve can be automatically switched by low oil pressure when the pressure of the flowing oil reaches a desired high value to cause the flow of oil to the ram to stop and the pressure to lower, a main cylinder, a balancing piston positioned for reciprocation in the main cylinder, a spring within the main cylinder at one end of the piston, an oil pump, an exhaust oil conduit, an oil tank with which the exhaust oil conduit communicates, a switch cylinder, a pilot piston in the switch cylinder, said main cylinder having a plurality of axially spaced grooves, a first of said grooves communicating with the oil pump via a receiving passage, a second of said grooves being open to a low pressure relief passage, a third of said grooves communicating with the oil pressure press via a delivery passage, and a fourth of said grooves communicating with the exhaust oil conduit via an exhaust oil passage, the reciprocation of the balancing piston directing oil flow into the delivery passage or the low pressure relief passage, selectively, a spring within the switch cylinder at one end of the pilot piston, the space around the spring being open to the exhaust oil passage, the space at the other end of the pilot piston being open to the low pressure relief passage, a check valve communicating with the space around the spring and being capable of opening and closing by the reciprocation of the pilot valve, an electro-magnetic switch valve arranged in the low pressure relief passage open to the space around the spring for the pilot piston via an electric valve, a check valve and a low pressure relief valve leading to one of the grooves in the main cylinder, a high pressure relief passage leading to the exhaust oil conduit via a high pressure relief valve, said high pressure relief passage having a branch from the delivery passage communicating with the space around the spring for the balancing piston via a throttle valve, and a further branch leading to a switch passage communicating with the check valve. 